Comparative immunohistochemical expression of β-catenin,EGFR,ErbB2,and p63 in adamantinomatous and papillary craniopharyngiomas

Craniopharyngiomas (cps) are rare epithelial tumors located mainly in the sellar/parasellar region. cps have been classified into histopathologically,genetically,clinically and prognostically two distinctive subtypes: adamantinomatous and papillary variants. aim: to determine the immunohistochemical expression of β-catenin,egfr,erbb2,and p63 in adamantinomatous and papillary cps. materials and methods: β-catenin,egfr,erbb2,and p63 immunostaining was performed on paraffin embedded tissue sections of 25 cps including 18 adamantinomatous craniopharyngioma (acp) and 7 cases of papillary craniopharyngiomas (pcps). results: 17 cases (94%) of acp exhibited strong nuclear/cytoplasmic expression of β-catenin. on the contrary,all cases of pcp showed exclusively membranous expression (p value. < 0.0001). regarding egfr,15 (83%) and 5 cases (71%) of apc and pcp respectively were positive. on the other hand,only 3 cases (17%) of apc and none of pcp exhibited positivity for erbb2. p63 over-expression was observed in 16 cases of acp (89%) and 6 cases of pcp (86%). however,the distribution of p63 staining was diffuse in acp,while in pcp; the staining was mainly restricted to the basal cell layer. conclusion: nuclear accumulation of β-catenin is a diagnostic hallmark of the acp and is very helpful in the differential diagnosis between both acp and pcp in the setting of small biopsies. moreover,the restricted nuclear β-catenin accumulation in the cohesive cell clusters within the whorl-like areas supports that aberrant β-catenin expression may play a role in the morphogenesis of acp. © 2015 the authors.